feat: F006 supply dashboard — complete spec implementation

- dataQualityService with getPortfolioQualitySummary()
- Service methods: getDashboardPropertiesSummary, getStrongMatches,
  getSignalSummary, getDashboardTasks added to respective services
- dashboardService uses Promise.allSettled for partial error resilience
- KpiCard: onClick + Tooltip support
- KpiGrid: navigate actions and tooltips per card
- StrongMatchMiniCard: Match Center, Prüfung, Vergleichen action buttons
- FutureSignalWidget: time horizon distribution (0–6, 6–12, 12–24 Mo.)
- SupplyDashboard: DashboardHeader, empty state, error state,
  partial widget errors, permission-based rendering per UserRole

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/domain/dashboard.ts

@@ -5,6 +5,8 @@ export interface KpiCardData {
   trend?: 'up' | 'down' | 'neutral'
   trendLabel?: string
   accent?: string
+  tooltip?: string
+  onClick?: () => void
 }
 
 export interface StrongMatchItem {
@@ -19,12 +21,19 @@ export interface StrongMatchItem {
   nextBestAction: string
 }
 
+export interface TimeHorizonDistribution {
+  short: number   // 0–6 months
+  medium: number  // 6–12 months
+  long: number    // 12–24 months
+}
+
 export interface FutureSignalSummary {
   total: number
   highConfidence: number
   restricted: number
   needsReview: number
   avgTimeHorizonMonths: number
+  timeHorizonDistribution: TimeHorizonDistribution
 }
 
 export interface DataQualitySummary {
@@ -47,9 +56,9 @@ export interface DashboardData {
   activeProperties: number
   strongMatchCount: number
   avgDataQuality: number
-  futureSignals: FutureSignalSummary
-  dataQuality: DataQualitySummary
-  reviewTasks: DashboardReviewTask[]
-  strongMatches: StrongMatchItem[]
+  futureSignals: FutureSignalSummary | null
+  dataQuality: DataQualitySummary | null
+  reviewTasks: DashboardReviewTask[] | null
+  strongMatches: StrongMatchItem[] | null
   lastUpdated: string
 }